TextArea: Detach the flickable when it is deleted

When the flickable is deleted before the TextArea is (which can happen
when it is a child of a ScrollView) then we need to make sure that the
TextArea no longer keeps a reference to the Flickable object.

Fixes: QTBUG-93958
Change-Id: I1745065370718e60bc459192e15eae0e1ba36231
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
(cherry picked from commit 4cba29c38cb1b610bf896130050b6c14b7e10c71)

2 files changed, 19 insertions, 0 deletions

diff --git a/src/quicktemplates2/qquicktextarea.cpp b/src/quicktemplates2/qquicktextarea.cpp
index bcc08c05..183c929e 100644
--- a/src/quicktemplates2/qquicktextarea.cpp
+++ b/src/quicktemplates2/qquicktextarea.cpp
@@ -318,6 +318,7 @@ void QQuickTextAreaPrivate::attachFlickable(QQuickFlickable *item)
     QObject::connect(flickable, &QQuickFlickable::contentYChanged, q, &QQuickItem::update);
 
     QQuickItemPrivate::get(flickable)->updateOrAddGeometryChangeListener(this, QQuickGeometryChange::Size);
+    QQuickItemPrivate::get(flickable)->addItemChangeListener(this, QQuickItemPrivate::Destroyed);
     QObjectPrivate::connect(flickable, &QQuickFlickable::contentWidthChanged, this, &QQuickTextAreaPrivate::resizeFlickableControl);
     QObjectPrivate::connect(flickable, &QQuickFlickable::contentHeightChanged, this, &QQuickTextAreaPrivate::resizeFlickableControl);
 
@@ -338,6 +339,7 @@ void QQuickTextAreaPrivate::detachFlickable()
     QObject::disconnect(flickable, &QQuickFlickable::contentYChanged, q, &QQuickItem::update);
 
     QQuickItemPrivate::get(flickable)->updateOrRemoveGeometryChangeListener(this, QQuickGeometryChange::Nothing);
+    QQuickItemPrivate::get(flickable)->removeItemChangeListener(this, QQuickItemPrivate::Destroyed);
     QObjectPrivate::disconnect(flickable, &QQuickFlickable::contentWidthChanged, this, &QQuickTextAreaPrivate::resizeFlickableControl);
     QObjectPrivate::disconnect(flickable, &QQuickFlickable::contentHeightChanged, this, &QQuickTextAreaPrivate::resizeFlickableControl);
 
@@ -522,6 +524,8 @@ void QQuickTextAreaPrivate::itemDestroyed(QQuickItem *item)
         background = nullptr;
         emit q->implicitBackgroundWidthChanged();
         emit q->implicitBackgroundHeightChanged();
+    } else if (item == flickable) {
+        detachFlickable();
     }
 }
 
diff --git a/tests/auto/controls/data/tst_scrollview.qml b/tests/auto/controls/data/tst_scrollview.qml
index 0dab4a63..78d62e35 100644
--- a/tests/auto/controls/data/tst_scrollview.qml
+++ b/tests/auto/controls/data/tst_scrollview.qml
@@ -193,6 +193,15 @@ TestCase {
             }
         }
     }
+    Component {
+        id: scrollableTextAreaWithSibling
+        ScrollView {
+            Item {
+            }
+            TextArea {
+            }
+        }
+    }
 
     function test_scrollBars() {
         var control = createTemporaryObject(scrollView, testCase, {width: 200, height: 200})
@@ -508,6 +517,12 @@ TestCase {
         compare(control.contentHeight, flickable.contentHeight)
     }
 
+    function test_textAreaWithSibling() {
+        // Checks that it does not crash when the ScrollView is deleted
+        var control = createTemporaryObject(scrollableTextAreaWithSibling, testCase)
+        verify(control)
+    }
+
     function test_customScrollBars() {
         let control = createTemporaryObject(scrollView, testCase)
         verify(control)